In this research, we utilize Southern California (SoCal) natural gas transmission pipelines and underground storage resources for transporting and storing hydrogen gas for a 100% renewable energy penetration. The goal is to determine to what extent natural gas infrastructure can be used to deliver and store hydrogen to meet SoCal electric demand for a 100% renewable energy portfolio. Hydrogen is produced from solar power generation using electrolysis next to the gas transmission pipelines whenever it is available in quantities greater than the electricity demand. It was found that using four main transmission pipelines owned by Southern California Gas company (SoCalGas) to transport hydrogen from the point of production to the four underground storage fields to store and later generate electricity through fuel cells can transport and store hydrogen sufficient to meet 40% of the SoCal electricity demand. That is, without any investment in additional transmission and distribution infrastructure, and without any investment in energy storage, the idea of building solar farms in the desert and using only the gas system for storage and transmission and distribution leads to a 40% increase in renewable electricity for the state.